Most blue gin gets its colour from the butterfly pea flower (Clitoria ternatea), steeped into the spirit. The flower holds a natural pigment that shows up deep blue in a neutral liquid. It shifts to purple and then pink when acid arrives, which is why a blue gin can change colour in your glass. A blue bottle, on the other hand, tells you nothing about the colour of the liquid inside.
That is the short answer. Below we cover the pigment, the pH trick, what the flower does to flavour, how to read an Australian label, and how to serve a colour-changing gin so it looks its best.
TL;DR
- Blue gin is usually coloured with butterfly pea flower, a natural source of blue pigments called ternatins, not a synthetic dye.
- The pigment reacts to acidity: blue in neutral conditions, purple with a little acid, pink with plenty. Tonic water and citrus are the usual triggers.
- The flower is very mild in flavour, so the taste of the gin comes mostly from its botanicals and style.
- A blue bottle does not mean blue gin. Check the label and the description to see where a gin’s colour comes from.
- Serve it in a neutral or lightly alkaline build for a blue drink, or add tonic or citrus for the colour change.
Table of Contents
- The flower behind the colour
- Why blue gin turns pink or purple
- Does blue gin taste different?
- What about gins that stay blue with acid?
- What does gin come from, and where does colour fit?
- Does a blue bottle mean blue gin?
- How to read an Australian label
- Serving blue and colour-changing gin well
- Perspective
- Find a naturally coloured gin you will love
- FAQ
- Sources
The flower behind the colour
The butterfly pea is a climbing plant long used in Southeast Asian herbal teas. Its petals are rich in anthocyanins, the same family of pigments that colour blueberries and red cabbage. The ones in butterfly pea are called ternatins. A peer-reviewed review published in August 2025 describes them as deep blue at neutral pH, purple in acidic conditions and greenish-yellow in alkaline conditions. It also notes that, unlike synthetic dyes such as FD&C Blue No. 1, they are used safely in the food industry.
The pigment is potent. A 2024 study of butterfly pea extraction measured far higher anthocyanin levels in fresh flowers (551,063 mg/L) than in dried ones (217,086 mg/L). It also confirmed the extract changes colour across the whole pH scale, from 1 to 14. That is why the flower works so well as a natural pH indicator, and why a small handful can colour a whole batch of gin.
Why the blue is so intense
Ternatins are built differently from the pigments in most other plants. One explanation is that the many aromatic groups attached to the pigment core fold around it like a protective shell. That shell gives an unusually stable, intense blue at a near-neutral pH, which is why butterfly pea stays vivid while blueberry or red cabbage extracts fade faster. It is a useful explanation, though the chemistry is still best treated as a good working model rather than the final word.
How the flower gets into the gin
The usual method is to infuse the flowers in the spirit, then let the colour develop. According to Quench Magazine, blue gins are infused with butterfly pea flowers, giving a blue to purple colour without detracting from the aromas or flavours. The same piece reports that Australia was where the trend started: a local distillery registered a trademark in 2013, held an innovation patent in 2015 and released its blue gin that year. A 2025 piece by a family distiller describes how the flower, common in Thai herbal teas but almost unknown in Australia then, turned a colour-changing gin into a conversation piece that helped spark the global pink gin movement.
Why blue gin turns pink or purple
The colour change is chemistry you can watch. Butterfly pea is the most pH-sensitive of the natural colourings: red at pH 2, violet between pH 4 and 6, and blue at pH 7. Add something acidic to a blue gin and the pH drops, so the colour moves along that scale.
In chemical terms, in an acidic solution the pigment molecule takes a form that reads reddish to purple. In a neutral to slightly basic solution it takes another form that reads intense blue, as explained here. Nothing is being added to the colour. The same pigment is simply rearranging itself.
What triggers the change
| Ingredient | Effect on acidity | Likely colour |
|---|---|---|
| Plain gin, neat or stirred | Neutral | Deep blue |
| Soda water | Slightly acidic from the carbonation | Blue shifting to violet |
| Tonic water | Acidic | Purple to pink |
| Lemon or lime juice | Strongly acidic | Pink |
| Dry vermouth or a splash of cordial | Varies by recipe | Violet to pink |
This is a guide, not a lab result. Exact shades depend on the gin, the amount of mixer and the ice. Distiller Magazine notes that butterfly pea is not pH stable: when acidity arrives as citrus or carbonated liquids, it moves from blue to purple to pink. The same article points out that a stirred martini offers the neutral or slightly alkaline conditions where the colour stays blue, while a spritz dilutes the spirit and the colour with it.
If you want to understand why acidity matters this much to how a drink looks and tastes, the elements of tasting are a good place to start: acid is one of the main levers on both flavour and appearance in any glass.
Botanicals can nudge the shade too
The gin’s own botanicals have a say. Acidic ingredients like citrus peel can lower the pH and push a blue gin toward purple, while alkaline ones such as liquorice root may raise it and lean the colour toward green. Higher alcohol strength also tends to hold the colour more steadily, according to this guide. So two blue gins can look different in the same glass of tonic.
Does blue gin taste different?
Not much. The point of the flower is colour, and it has a very light touch. An Australian herb supplier describes butterfly pea as essentially flavour-neutral: mild, earthy and a little woody, rather like a weak unsweetened green tea. Quench Magazine reports that blue gins taste like typical gin, and quotes a Victorian distiller who says the flower can add an earthy, grounding note and a softer, rounder texture, a bit like angelica root does in some recipes.
In practice, the taste of a blue gin comes mostly from its juniper, citrus and other botanicals, and from how carefully it has been distilled. The colour is the visual bonus.
Why some blue gins fade
Natural colour is a living thing. One head distiller told Artisan Spirit Magazine that the colour change starts the moment the flower meets the spirit, and that early batches lost their colour entirely after about a month, turning brown. Makers have since learned how to manage this. The same source notes that sugar can prolong colour stability provided the pH stays constant, with sucrose, glucose and maltose all helping. For drinkers, the takeaway is simple: keep your bottle out of strong light and heat, and enjoy it while it looks its best.
What about gins that stay blue with acid?
Some producers want a blue that does not move. Distiller Magazine mentions huito fruit (Genipa americana), whose iridoid blue pigments are stable in acidic conditions, giving a naturally derived blue at a pH lower than neutral. It is a reminder that “blue” can come from more than one natural source, and that the source decides how the gin behaves with tonic.
What does gin come from, and where does colour fit?
A fair question to ask while we are here. Under the Australian Food Standards Code, a spirit is a potable alcoholic distillate, including gin, made by distilling fermented liquor from food sources so that it has the taste, aroma and characteristics generally attributable to that spirit. In the classic description of gin, as quoted by an Australian bartender, the spirit is made by redistilling neutral ethyl alcohol of at least 96% vol. in the presence of juniper berries, with juniper the predominant taste.
Colour is not part of that definition. Gin is juniper-led first. Whether it is clear, blue or pink is a choice the maker makes about the finished spirit. If you want to understand how methods differ, our guide to compound gin versus distilled gin explains what sets them apart.
Does a blue bottle mean blue gin?
No. Tinted glass is a styling choice. One US craft release, for example, came in blue-tinted bottles that subtly masked the clear liquor inside. Plenty of famous gins sit in blue glass and pour crystal clear. If the colour matters to you, look at the description and at the liquid itself, not at the bottle.
How to read an Australian label
Labels in Australia follow the Food Standards Code, and the name of the product has to describe what is actually in the bottle. A few practical cues help you work out where a colour comes from:
- Read the description. Look for wording that names the botanical, such as a flower infusion, and not simply a colour.
- Check the ingredient list where one is given. Naturally derived colours such as anthocyanins are named. Australian rules permit anthocyanins (INS 163) as a food colour in specified products, with limits on total added colour in beverages.
- Watch for claims like “natural” or “no additives”. These are the maker’s own statements, so it is worth reading the maker’s own page to see what they mean in full.
- Notice the behaviour. A gin that shifts from blue to pink with tonic is almost certainly relying on a pH-sensitive plant pigment.
Serving blue and colour-changing gin well
The fun of a colour-changing gin is the reveal, so build the drink to show it off.
- For a blue drink: stir the gin with ice and strain into a chilled glass, or keep mixers neutral. A simple martini-style serve keeps it vivid.
- For the colour change: pour the gin over ice first, then add tonic or a squeeze of citrus at the table. The gradient from blue to violet to pink is the show.
- For pink in one go: build it with tonic and a wedge of lemon or lime, and it will land on pink.
- Keep it cold and fresh: big ice dilutes more slowly, so the colour stays consistent for longer.
We have written up three cocktail builds for colour-changing gin if you want recipes, and our guide to bottle-ready gin and tonic garnishes shows how a garnish can add aroma as well as a splash of acidity.
Perspective
We make gin the way we like to drink it: flavour first, with thoughtfully selected, locally sourced botanicals and a carefully handled distillation. Colour is part of the pleasure, and we like it to come naturally.
That is why our range includes naturally coloured spirits, vegan and gluten free, made without additives. When a gin looks as good as it tastes, you do not need a gimmick to sell it. You need a balanced, expressive spirit in the glass and a colour that tells the truth about what went into it.
Our advice if you are curious about colour-changing gin is to treat the colour as a bonus, not the main event. Choose the gin whose flavour you love, then play with the serve. Add tonic, a little citrus, or a garnish and watch the glass change. If you are unsure where to start, our gin matching quiz is designed to point you toward a style that suits your palate: tailor-made spirits, naturally vibrant.
Winston
Find a naturally coloured gin you will love
If the colour side of gin has caught your eye, start with our Pink Fit gin, then browse the full Denim Collection for more expressive, naturally coloured spirits. Each one is crafted from natural botanicals and designed to stand out in the glass.
Prefer to see everything at once? Our gins collection has the lot, and our tonics make it easy to pair a bottle with the right mixer. If you are still deciding, our practical guide to choosing a gin walks through styles, flavours and occasions.
FAQ
What turns gin pink?
Acid. In a gin coloured with butterfly pea flower, tonic water, lemon or lime juice lowers the pH, and the pigment shifts from blue through purple to pink. The more acid you add, the pinker the drink becomes.
Is blue gin natural?
Often, yes. Many blue gins use butterfly pea flower, a plant source of blue pigment, rather than a synthetic dye. Because makers can colour gin in different ways, check the label or the maker’s own description for how a particular bottle is coloured.
Does blue gin taste different from regular gin?
Only slightly. The flower is very mild, with a faintly earthy, tea-like character, so the flavour of the gin comes mostly from its juniper and other botanicals. Some distillers say it can add a touch of softness or roundness to the texture.
Which gin comes in a blue bottle?
Several do, and the bottle says nothing about the liquid. Blue glass is a design choice, and plenty of gins in blue bottles are completely clear. Always check the description and look at the liquid itself.
Sources
- Exploring Clitoria ternatea: a review of its therapeutic and industrial promise (IJPREMS)
- Anthocyanin extraction and pH-modulated colour alterations (IOPscience)
- Blue Gin: Gimmick or Cocktail Essential? (Quench Magazine)
- The indigo revolution (Food & Drink Business)
- Blue has sold a lot of gin (Artisan Spirit Magazine)
- The Power of Color (Distiller Magazine)
- Blue gin or vodka: how to make the magical colour change (Danish Things)
- Butterfly Pea Flowers Whole (Herbal Connection)
- Food Standards Code compilation, May 2025 (FSANZ)
- Eight things you should know about gin (Australian Bartender)
- Origin gin announcement (The Manual)
- Food Standards Code Standard 1.3.1 compilation (legislation.gov.au)
- The Elements of Tasting (Blame It On Bacchus)
